The research proposed in this application is to develop an understanding of the changes which occur in the spinal cord in the first few hours following a traumatic injury which will result in a paralysis below the level of injury. This information cannot be obtained from human material, only from the study of animals. For this purpose we have chosen the monkey (Macaca mulatta), but cats are also being used for the development of new techniques which will ultimately be transferred to the studies on primates. Until our studies were begun under the original grant in January 1970, only very limited and superficial information was available. In the less than two years that we have been working, considerable knowledge has been gained but the study is by no means complete. The work thus far has been largely confined to the study of blood flow, of the structural changes which progressively develop following injury, and of the development of edema. In addition to pursuing the studies in these areas we propose, under other research grants, to study physiological changes occurring at the site of injury, and both structural and physiological changes which occur in the spinal cord below the site of injury.